/ 
Graph-Weighted-0.5601
River stage zero No dependents
/ Graph::Weighted

NAME

Graph::Weighted - A weighted graph implementation

VERSION

version 0.5601

SYNOPSIS

use Graph::Weighted;

my $gw = Graph::Weighted->new();
$gw->populate(
   [ [ 0, 1, 2, 0, 0 ], # Vertex 0 with 2 edges of weight 3
     [ 1, 0, 3, 0, 0 ], #    "   1      2 "               4
     [ 2, 3, 0, 0, 0 ], #    "   2      2 "               5
     [ 0, 0, 1, 0, 0 ], #    "   3      1 "               1
     [ 0, 0, 0, 0, 0 ], #    "   4      0 "               0
   ]
);
for my $vertex (sort { $a <=> $b } $gw->vertices) {
   warn sprintf "vertex: %s weight=%.2f\n",
       $vertex, $gw->get_weight($vertex);
   for my $neighbor (sort { $a <=> $b } $gw->neighbors($vertex)) {
       warn sprintf "\tedge to: %s weight=%.2f\n",
           $neighbor, $gw->get_weight([$vertex, $neighbor]);
   }
}

my ($lightest, $heaviest) = $gw->span();
my $weight = $gw->path_attr(\@vertices);

my $gw = Graph::Weighted->new();
my $attr = 'probability';
$gw->populate(
   {
       0 => { 1 => 0.4, 3 => 0.6 }, # Vertex 0 with 2 edges of weight 1
       1 => { 0 => 0.3, 2 => 0.7 }, # Vertex 1 "    2 "
       2 => { 0 => 0.5, 2 => 0.5 }, # Vertex 2 "    2 "
       3 => { 0 => 0.2, 1 => 0.8 }, # Vertex 3 "    2 "
   },
   $attr
);
for my $vertex (sort { $a <=> $b } $gw->vertices) {
   warn sprintf "vertex: %s %s=%.2f\n",
       $vertex, $attr, $gw->get_attr($vertex, $attr);
   for my $neighbor (sort { $a <=> $b } $gw->neighbors($vertex)) {
       warn sprintf "\tedge to: %s %s=%.2f\n",
           $neighbor, $attr, $gw->get_attr([$vertex, $neighbor], $attr);
   }
}

DESCRIPTION

A Graph::Weighted object is a subclass of the Graph module with attribute handling. As such, all of the Graph methods may be used as documented, but with the addition of custom weighting.

METHODS

new()

my $gw = Graph::Weighted->new;

Return a new Graph::Weighted object.

Please see Graph for the possible constructor arguments.

populate()

$gw->populate($matrix);
$gw->populate(\@vectors);
$gw->populate(\@vectors, $attribute);
$gw->populate(\%data_points, $attribute);

Populate a graph with weighted nodes.

For arguments, the data can be a numeric value ("terminal node"), an arrayref of numeric vectors, a Math::MatrixReal object, or a hashref of numeric edge values. The attribute is an optional string name, with the default "weight."

Examples of data in array reference form:

[]      1 vertex with no edges.
[0]     1 vertex and 1 edge to node 0 having weight of 0.
[1]     1 vertex and 1 edge to node 0 weight 1.
[0,1]   2 vertices and 2 edges having edge weights 0,1 and vertex weight 1.
[0,1,9] 3 vertices and 3 edges having edge weights 0,1,9 and vertex weight 10.

Multiple attributes may be applied to a graph, thereby layering and increasing the overall dimension.

get_weight()

$w = $gw->get_weight($vertex);
$w = $gw->get_weight([$vertex, $neighbor]);

Return the weight for the vertex or edge.

A vertex is a numeric value. An edge is an array reference with 2 elements. If no value is found, zero is returned.

get_attr()

$w = $gw->get_attr($vertex, $attribute);
$w = $gw->get_attr(\@edge, $attribute);

Return the named attribute value for the vertex or edge.

span()

my ($lightest, $heaviest) = $gw->span();
my ($lightest, $heaviest) = $gw->span($attr);

Return the span of lightest to heaviest vertices.

path_attr()

my $weight = $gw->path_attr(\@vertices);
my $weight = $gw->path_attr(\@vertices, $attr);

Return the summed weight (or given attribute) of the path edges.

TO DO

Find the total weight beneath a node.

SEE ALSO

Graph

The eg/* and t/* file sources.

AUTHOR

Gene Boggs <gene@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2015 by Gene Boggs.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.